The definition given by VAN TIEGHEM (2I), and usually adopted, is as follows: The leaf is symmetrical on both sides of a plane; the shoot is symmetrical around an axis. A needle is symmetrical on both sides of a plane, not around an axis; but by bringing into contact the different needles grouped at the end of a spur shoot, an organ is obtained which is symmetrical around an axis, and which therefore is a shoot. Needles, therefore, are fragmentary shoots. Anatomically they are polystelic shoots which have divided longitudinally into a variable number of parts' in order to increase the surface available for carbon assimilation. Being fragmentary shoots, the needle may be considered the homologue of the petiole of broad-leaved gymnosperms. The anatomy of the needle is strikingly similar to that of the petiole in Ginkgo, and we may quote COULTER (4) as follows: "The most ancient gymnosperms possessed ample fernlike leaves ... . The conifers, however, have developed a very different type of leaf . . . . which reaches an extreme expression in small and rigid needles." The derivation of needles from fernlike phyllodes is apparent from anatomical data.